This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an example described below, more particularly provides for rapid setting and unsetting of a swellable packer.
Swellable materials have been used in the past to perform various functions in well tools. For example, a swellable material may be used in a packer seal element to provide a packer assembly which is self-actuating downhole. When an appropriate fluid contacts the swellable material, the material swells and seals off an annulus in the well.
However, it can take many hours or even days for conventional swellable materials to swell in a well. Rig time is very expensive, and so this is a disadvantage to use of conventional swellable materials. In addition, once swollen, such materials are not generally un-swellable, or even if they could be un-swollen, this would take very long periods of time, and would be unpredictable.
Therefore, it will be appreciated that it would be desirable to provide improvements in the art of swelling and un-swelling swellable materials in subterranean wells. Such improvements could be useful for initiating actuation of packer assemblies, as well as other types of well tools.